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Finding the Fourth Proportional to 682.40, 1,022.82 and 390.05

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Solution

The fourth proportional to 682.40, 1,022.82 and 390.05 is: 584.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    682.40 : 1,022.82 = 390.05 : x
  2. Step 2: Convert to fraction form
    682.40/1,022.82 = 390.05/x
  3. Step 3: Cross multiply
    682.40x = 1,022.82 × 390.05
  4. Step 4: Simplify right side
    682.40x = 398,950.94
  5. Step 5: Solve for x
    x = 398,950.94/682.40
  6. Step 6: Final answer
    x = 584.63

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.